What is the recommended action after a disconnecting a cannon plug on a fuel shutoff valve?

After disconnecting a cannon plug on a fuel shutoff valve, the recommended action is to immediately close the valve. This step is crucial for maintaining safety and preventing potential hazards. The fuel shutoff valve plays a vital role in controlling the flow of fuel to the engines, and disconnecting the cannon plug can result in an open state that might lead to fuel leaks or spills. By closing the valve right away, you effectively mitigate the risks associated with an open fuel system, ensuring that no fuel is inadvertently released into the environment or onto the aircraft.

Addressing other options, leaving the valve unplugged for safety would not provide adequate protection, as it could allow fuel to flow uncontrollably. Informing the flight crew is important but does not address the immediate risk posed by the valve being open. Checking for leaks should ideally follow the closure of the valve to ensure that there are no issues, but it should not come before the valve is securely closed. Therefore, closing the valve immediately is the most critical and appropriate action to take in this situation.